The Ecosystems Research Center (ERC) was established at Cornell U ni- versity in October 1980 by the Environmental Protection Agency (EPA) with the goals of: 1. Identifying fundamental principles and concepts of ecosystems sci- ence and the determination of their importance in understanding and pre- dicting the responses of ecosystems to stress, the description of the basic mechanisms that operate within ecosystems, and an examination of the stability of ecosystem structure and function in the face of stress. 2. Testing the applicability of those theoretical concepts to problems of concern to...